I wonder if such asteroids get hit by other asteroids in such a way that they get leading and trailing chunks flying alongside that actually would enter our atmosphere before or after the big one passes by?

Ninja Otter:I still wonder just how difficult it would be to capture one of these asteroids and put it in a stable orbit around the earth, for a future base/resource for space missions.

Depends upon the orbit really. But essentially you would probably need to add change its velocity probably about 1000 m/s on average. The asteroid that hit Russia the other month was about 9 million kilograms. This 2 mile wide one would be many times larger, lets so with 100 million (its probably in the billions).50,000,000,000,000 J or 50,000,000 megawatt/hours or 50,000 gigawatts/hours. The US total power generation capacity is just over 1000 gigawatts